Tungsten Metallurgy Method

Tungsten metallurgy products mainly include ammonium paratungstate, tungsten trioxide, blue tungsten oxide, violet tungsten oxide, tungsten powder, ammonium metatungstate, tungsten carbide powder. Ammonium paratungstate is the main intermediate product and the raw material in tungsten metallurgy products.

Tungsten metallurgy method from tungsten concentrate to ammonium paratungstate include tungsten concentrate degradation, tungsten chemical compound purification and tungsten powder metal production. The main producing method of tungsten powder includes acidity method which is basically outdated, ion exchange method and hyamine alkali extraction method.

Ion Exchange Method
Process of ion exchange method is by mixing tungsten concentrate with NaOH solution, WO₃ exist in Na₂WO₄ as solution, then absorb it by Cl type alkali ion exchange resin to obtain WO₄^2-, desorb by NH₄CL+NH₄OH solution, purifying molybdenum and after evaporation to get ammonium paratungstate. It is developed independently by China which is the leading process in the world. It has the most widely application in China which takes up 85%. It is widely applied due to its short process, little deficiency in tungsten, high recycle rate which reaches 96.3%, high purification efficiency, low corrosion property, less equipment and easy to operate, environmental friendly and can realize machine automatically. Salient disadvantages such as large water consuming amount, water emission amount and subsidy amount.

Hyamine Alkali Extraction Method
Primary process of extraction method is similar to ion exchange method. Obtain Na₂WO₄ solution by resolving tungsten concentrate with NaOH, then purifying by magnesium sedimentation method, transform by hyamine, after evaporation to get APT. This method need to consume a lot of aqueous alkali, eliminating a lot of impurities which is insoluble in alkali solution. Subsidies after purification will return to autoclaving process, then emission in form of autoclaving subsidies. As a result, the produced subsides can reach 40%.

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